121 research outputs found

    Hydrogen trapping by VC precipitates and structural defects in a high strength Fe-Mn-C steel studied by small-angle neutron scattering

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    The trapping of hydrogen by VC precipitates and structural defects in high strength Fe-Mn-C steel was studied by small angle neutron scattering. No interaction between H and V in solid solution has been detected but a significant interaction between H and structural defects introduced by plastic deformation has been measured. This last effect was reversible upon outgassing of the H. Moreover a significant interaction between H and VC precipitates has been measured; 5 ppm wt. of H could be trapped in the precipitates. This is consistent with the homogeneous trapping of H within the precipitates rather than at the precipitate/matrix interface

    Altimetry for the future: Building on 25 years of progress

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    In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the ‘‘Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

    COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

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    Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

    Cryopreservation of embryos : a way to reduce the number of housed animals and the genetic drift.

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    The GIGA Mouse facility platform has recently improved its mouse line cryopreservation technique. The method of embryo cryopreservation by rapid cooling also called aseptic vitrification has been selected. Vitrification media, key steps and timing have been optimized and validated. After a first partial exposition of the embryos to cryoprotective solutions, they are immersed in a vitrifying mixture of penetrating and non-penetrating cryoprotectants for a short time. The straw containing the embryos is immediately sealed before to be plunged in LN2, resulting in a brutal solidification in which crystallization does not have time to occur

    Programming with first-class modules in a core language with subtyping, singleton kinds and open existential types

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    en français : Cette thèse décrit comment l'ajout de trois ingrédients à Système F permet d'écrire des programmes de façon modulaire dans un système explicite à la Church, tout en gardant un style proche des modules de ML. Le premier chapitre s'intéresse aux types existentiels ouverts, qui confèrent la possibilité d'utiliser des types existentiels sans restriction de portée : cela offre une plus grande flexibilité dans l'organisation des programmes. Le deuxième chapitre est consacré à l'étude des kinds singletons, qui modélisent les définitions de types : dans ce cadre, on donne une caractérisation simple de l'équivalence de types, fondée sur une relation de réduction confluente et fortement normalisante. Le dernier chapitre intègre les deux notions précédentes dans un langage noyau muni d'une relation de sous-typage : cela apporte à F un gain de modularité important, de niveau comparable à celui des modules de ML. Une traduction des modules vers ce langage est esquissée, permettant une comparaison précise des deux langages.en anglais : This thesis explains how the adjunction of three features to System F allows writing programs in a modular way in an explicit system à la Church, while keeping a style that is similar to ML modules. The first chapter focuses on open existential types, which provide a way to consider existential types without scope restrictions: they permit to organize programs in a more flexible manner. The second chapter is devoted to the study of singleton kinds, which model type definitions: in this framework, we give a simple characterization of type equivalence, that is based on a confluent and strongly normalizing reduction relation. The last chapter integrates the two previous notions into a core language equipped with a subtyping relation: it greatly improves the modularity of F to a level that is comparable with the flexibility of ML modules. A translation from modules to this core language is defined, and is used to precisely compare the two languages.PALAISEAU-Polytechnique (914772301) / SudocSudocFranceF

    Artérialisation systémique du poumon sans séquestration (à propos de 13 observations)

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    LILLE2-BU Santé-Recherche (593502101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

    Vulnérabilité aux conduites suicidaires (étude de la perception et de l'impact de la douleur physique et morale)

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    MONTPELLIER-BU Pharmacie (341722105) / SudocSudocFranceF

    GIGA ANIMAL CARE : Mice & Zebrafish Animal Facility and Transgenesis

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    In fundamental research, animal models allow to place molecular and cellular observations back into their physiological context. In applied research, these models still remain a mandatory step to evaluate the efficiency and the toxicity of potential treatments, before going to clinical trials. Mouse and Zebrafish (Danio rerio) are two very interesting models because of a short live cycle and a high prolificacy. They require a limited space. Their genome is well known and shows a high homology with the human. Many tools are available to produce transgenic mice or zebrafishes. Many tests are validated using both these species
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